Optimizing the preparation parameters of GO and rGO for large-scale production

Preparation of graphene from chemical reduction of graphene oxide (GO) is recognized as one of the most promising methods for large-scale and low-cost production of graphene-based materials. Hummers' method (KMnO4, NaNO3, H2SO4) is the most common method used for preparing GO. Excluding NaNO3 and optimizing the acids ratios of H2SO4/H3PO4 in order to improve the efficiency of the oxidation process is the target of this study. The chemical reduction of GO involves highly toxic reducing agent (hydrazine) that are harmful to human health and environment, and complicated surface modification is often needed to avoid aggregation of the reduced GO (rGO) during reduction process. An innocuous, safe, and efficient reducing agent (ascorbic acid/L.AA) was used for GO reduction. The measurements of the resultant graphene confirm the efficient removal of the oxygen-containing groups in GO. The 2 h-rGO-L.AA shows a higher C/O ratio (6.07) than 24 h-rGO-Hy. Since L.AA has excellent antioxidant activity and is widely available, it is reasonable to consider L.AA as a green, effective, and low-cost deoxygenation agent for mass production of rGO.